Fluid atomizer



March 27, 1945. L. KoolsTRA FLUID 'ATOMIZER Filed Feb. 11, 1941 2 sheets-sheet 1 Fig.

m. m v m VPatented Mar. 27, 1945 FLUID Aromzaa.

Lambert Kooistra, Akron, Ohio, assigner to Babcock b Wilcox Company, Newark, N. J.,

The` a.

corporation of New Jersey v Application February 11, 1941, serial No. 378,369

18 Claims.

The invention herein disclosed relates to a uid atomizer particularly applicable to a fluent fuel burner in which a liquid fuel vis atomized mechanically as a result of being forced under pressure through a suitable outlet orifice. The fuel is preferably made to enter the orifice at a relatively high angular velocity by providing a whirl chamber within the burner tip and directing the liquid fuel into the chamber in one or more tangential streams to impart a rotary motion, thereby causing the fuel to be sprayed from the orifice in the form of a hollow cone as a result of the centrifugal action.

In burners heretofore constructed, it has been customary to maintain a ilxed ratio between the area of the tangential flow passages through which fuel is delivered to the whirl chamber and the area of the orifice through which fuel is discharged from the chamber. Such burners have been available for operation at.dii!erent now capacities by regulating the pressure of the fuel supplied; however, the permissible range of capacity has been substantially limited, due to the necessity for maintaining an acceptable quality 'f of atomization throughout for optimum combustion characteristics. In practice, the range of operation has been about 2:1 for pressures from about 50 lbs. per sq. in. at minimum capacity to about 300 lbs. per sq. in. at maximum capacity. In a boiler installation for example where a wider range of capacities might be desired it has been necessary to utiliml a plurality of burners and operate a different number of burners for each step in capacity. The alternative would be to interrupt operation and substitute a different burner or different burner parts.

The more general objects of this invention therefore include the development of an atomizer which may be operated over an extended range of flow capacities as distinguished vf rom the relatively narrow normal operating range of prior art devices for equivalent quality of atomization; an atomizer wherein the same assembly of parts may be used throughout the entire operating range; and, an atomizer operable over a wide range of capacities with the liquid to be atomized supplied either at a constant pressure, or at different pressures.

Additional objects of the inventionv pertain a regulation of flow capacity by varying the ratio between the tangential passage or port area and the area of the outlet orifice; for example. for a given area of outlet orifice, the tangential ow area may be increased for an increase in capacity and decreased for a decrease in capacof the tangential port or ports which increases the ratio, will tend to reduce the spray angle,

and a decrease in the now area which decreases the ratio. will tend vto expand the spray angle.

The effect on spray anglemay be more pro- Y nounced in an atomizer of the wide range type wherein the ratio of port to orice area is varied, than in an atomizer of a more limited range wherein the ratio of port to orifice area is fixed,

due to variations in the relative effectiveness'` of forces acting on the liquid as `it passes through the orifice; the 4centrifugal force resulting from the rotational movement within the whirl chamber tending to expand the angle and the axial force due to the pressure differential across the orifice tending to contract the angle. In an atomizer of the type shown, wherein the area of orifice is fixed, if the pressure of fuel at the entrances to the ports is maintained constant, anincrease in capacity obtained by increasing the port area results in al decreased angle oi' spray; however, for an equivalent change in the rate of fuel flow if the entrance pressure is increased simultaneously with an increase in port area, it is found that the decrease in spray angle is less than with constant pressure. By combining the pressure variations in suitable relation to the variations in port area, assuming an orifice of constant area as shown, it is possible to operate over a substantial range of flow capacities, of at least 6 or 8 tolfor example, without appreciable variation in the angle of spray. The ow capacity may also be regulated by continuously varying fuel pressure throughout the range in combination with step-by-step adjustment of the port area.

Since it is desirable to operate with a substantially constant and reasonably wide angle of spray throughout a given capacity range, a further object of the invention is to maintainja'condition of now to and through the orifice such that the rotational velocity of the liquid at thevarious capacities is sufllcient to modify the effect of the axial force tending to cause a reduction in the spray angle as the output is increased.

Other objects of the invention will be apparent as the speciilcationproceeds. as will the advantages which are derived from its utilization in various embodiments. as illustrated for example in the accompanying drawings, wherein:

Fig. 1 is a longitudinal section of a burner assembly;

Fig. 2 is a fragmentary detailed enlargement of F18. 1;

Fig. 3 is a transverse section along line 3 3 of Fi .2;

gig. 4 is a transverse section along line 4-4 of Fig. 2 showing the relation of parts for maximum capacity;

Fig. 5 is a'view similar to Fig. 4 showing the relation of parts for reduced capacity;

Figa 6 is a fragmentary enlargement, similar to Fig. 2 and partly in section, illustrating a modification; Figs. 7 and 8 are end views of parts shown cooperatively assembled in Fig. 6:

Fig. 9 is a diametral section of the part shown in Fig. 7:

Fig. 10ris a diametral section of the part shown in Fig. 8i

Fig. 11 is a transverse section of in Fig. 6, taken along line ll-ll;

Fig. 12 is a fragmentary enlargement. in section, showing a modification of the structure of Fig. 6; and,

Fig. 13 is a longitudinal section, similar to Fig. l, showing a modified burner arrangement.

In detail, the burner assembly of Figs. 1-4 includes a body portion l0 to which a barrel I2 is securedby a threaded connection I4, the barrel being fitted with an orifice plate I6 which is held in position at the end of the barrel by means of a cap I8 having a threaded connection with the barrel as at 20. The fuel to be atomized is admitted under pressure to an interior chamber 22 of the burner body through an inlet port 24 and passes througha passage 26 within the barrel l2, and through other passages to be described, for discharge through the outlet orifice 28 in plate I6. The spindle 80 which is rotatable t0 effect a control of fuel flow to the orice, extends 1ongitudinally of the barrel passage 26 and is supported concentrically therein to provide an annular fuel flow space 82, the support being provided by an enlargement 34 at one end of the spindle which is in circumferential engagement with the wall of the passage. The longitudinal grooves or slots 86 in the enlarged portion 34 provide passages for conducting fuel from the annular space 32 about the spindle to the annular space 38 within the counterbore 40 at the end of the barrel. each slot passage having a curved base portion 42 for directing each stream of` fuel gradually into the counterbore space 38 at`the greater diameter. The opposite end portion 44 of the spindle of reduced diameter is extended exteriorly of the body for convenient control of its rotative movement. The control may be accomplished manually for example by attachment of a hand wheel or lever 45 attached to the spindle extension 44 for rotation relative to a fixed dial or scale 41; or its movement may be automatically controlled' by suitable known powering means, which in a boiler installation may operate to rotate the spindle in response to variations in pressure of the outgoing vapor, or to some other variable indicative of a demand for more or less fuel.

parts shown;

The adjacent end of the burner body I 8 is closed by a housing 48 having a connection as by threads 48 with the body, and providing a seat 58 for a spring 62 which serves to continuously exert pressure longitudinally of the spindle 30 tending to force the spindle in the direction of the orice plate for a purpose which will later be made apparent. The spring pressure may be transmitted to the spindle through a washer 64 and spacer collar 66 which latter part is seated against a shoulder 68. Leakage of pressure uid from within the body III is prevented by the packing which is confined within the counterbore 52 by a gland 84 and by a packing nut 66 having a threaded connection 68 with the housing 46.

Referring .particularly to Figs 2, 3 and 4, the

fuel from the annular space 82 is directed substantially tangentially into a whirl chamber 10 of circular cross-section through one or more passages or ports 12 whereby the fuel attains a high angular velocity prior to its discharge through the axially disposed outlet orifice 28. The chamber 18 which may be formed in part within the orifice plate I6 as shown is of substantial depth and preferably includes a cylindrical base portion 'I4 through which fuel is admitted. the wall portion 16 adjacent the orifice being substantially normal to the orifice axis.

In the selected embodiment, the tangential passages are provided by a ow control unit I8 consisting of a series of plates 80 which are disposed in an annular band adjacent the inner surface 82 of the orifice plate I6, each plate being of generally sectoral outline and having a pin-bearing 84 on the orice plate I6 for limited rotational movement relative to adjacent plates whereby the width of the tangential passages 12 may be varied. The depth of each port is constant, that lis the dimension longitudinally of the burner axis, and is determined by the thickness of the plates 80 which are surfaced in parallel planes at opposite sides to provide close engagement with mating surfaces 82 and 86 on the orifice plate I6 and spindle 30, respectively. The contacting relation of the assembled parts is maintained throughout operation by means of spring 62 which vcontinuously and resiliently holds the end of spindle 38 f in contact with the plates 80 and the plates 80 in contact with the orifice plate l 6.

The plates 80 are slotted as. at 88 to receive pins v 90 which are mounted in the end of spindle 30.

the slot in each plate being elongated in a direction parallel to the edge 82 which is at the greater radial distance from the central axis of the whirl chamber 10. The edge 92 may be curved at its inner end portion as at 94 to coincide with the cylindrical wall portion 'I4 of the chamber, while the other edge 96 may extend in a substantially straight line toward the whirl chamber at a lesser radial distance from the axis. The tangential passages 12 are thus defined by the adjacent edges 82 and 96 of adjacent plates 80 which edges, in the illustrated embodiment, are parallel to each other and remain in that relation throughout their relative movement. With such an arrangement, each tangential passage is of substantially constant flow area throughout its extent in the direction of the whirl chamber, but it is contemplated that a varying flow area may be provided if desired by suitable formation of individual plates; for example, in an arrangement of four plates as shown, the angle between edges 92 and 98 is 90. whereas a permissible deviation from this right angled relation would provide passages of tapering cross-section. It is also contemplated that a different number of tangential passages may be provided, more or less than four,.by suitable selection of the size and number of plates 80. and of the angle between edges 92 land 06 of each late. p The width of the passages 212 is varied by rotating the spindle 30 through a desired angle and thereby causing the pins 90 acting in slots 08 to rotate the plates 80 through a proportionate angle about their respective bearing pins 84, the edge of each plate beingrounded as at 98 to clear the wall of the counterbore 40 during rotation.

As seen in Fig. 4, the plates are at their extreme `position of clockwise movement to provide the "maximum width of tangential passages 12, in

which position the wall of-counterbore 40 at the end of the barrel I2 serves as a stop for the outercircumferential edges of the plates which are of substantially the same radius as that 0f the counterbore. lAs seen in Fig. 5, the plates are in an intermediate position to provide an intermediate width of tangential passages 12, the plates having been rotated in a counterclockwise. direction from their full open position (Fig. 4) by an opposite rotation of spindle which carries the actuating pins 90. A fine degree of adjustment is available with this arrangement, since the angular displacement of plates 80 about their respective pivots 84 is substantially less than the angular movement ofthe operating spindle 30, the ratio being approximately 1:10 for parts of the proportions shown. The slots 88 are Preferably of a length to -permit counterclockwise rotation of the plates 80 to a fully closed position, that is where an edge 92 of one plate contacts an edge 96 of an adjacent plate; however, shorter slots may be provided, if desired, to limit the extent of closing movementand thus fix the minimum operating width of the tangential passages.

It will be noted from Fig. 5 that as the plates 80 are moved from the full open position, the curved inner portions 94 of the plate edges 92 are moved inwardly from their original circumferential location at the diameter 14 of the whirl chamber |J, thus gradually reducing the effective diameter of the whirl chamber at the point of fluid admission and causing an increase in the angular velocity of the whirling mass.

An additional feature of the arrangement is that there is a minimum possibility of liquid reaching the whirl chamber except through the tangential passages 12 through which flow is lntended. The contacting planar surfaces on the flow control unit 18, the orifice plate 82 and the spindle 30 may be ground to an accurate fit to preclude leakage of liquid between the joint surfaces of the relatively movable parts, the continuous pressure of spring 52 automatically compensating for any wear of the companionate joint surfaces. It is also to be noted that with the described arrangement there is ample provision for expansion and contraction of the cooperating elements, due to temperature changes, without interference with the operating characteristics of the atomizer.

Fig. 6 illustrates a modified assembly of atomizer elements for controlling the flow of fuel to the whirl chamber and office. The barrel I2, having a bore passage 26 as in the former embodiment, is fitted with an orifice member |02 at its outer end, the orifice member being centered within the counterbore |04 by means of the shoulder surface |06 and rigidly held in position by means of the cap |08 which may be secured to the barrel as by threads H0.

. have companionate facing surfaces and |42 The outer face of the orifice member |02 may be conically recessed as at I|2 to provide a surface flaring outwardly from the orlce ||4 at an apex angle of about The member |02 may alsoL be recessed at its inner face to provide a whirl chamber ||6 concentric with and immediately adjacent the orifice ||4, and as shown, may include a conical surface portion ||6 converging toward the orifice in the direction of fuel flow at an apex angle of about 60.

A rotatable member |20 cooperates with the fixed orifice member |02 to provide a base surface |22 for the whirl chamber H6, an adjacent cylindrical wall portion |66, additional to and concentric with the conical wall portion H8. and to provide one or more flow passages or ports |24 of tapering cross section through which fuel is directed into the whirl chamber substantially tangentially of the cylindrical wall portion |56. y

The member |20 is supported within the counterbore |04 by circumferentially spaced ribs |28 while the intervening grooves or slots |28 provide passages for the flow of fuel into the annular counterbore space |30 at the entrances to the tangential passages |24. The member is 'formed at its inner end with a counterbore |32 formed with intermeshing teeth |44 in a manner similar to the working surfaces of the spiral form of clutch as used for making and breaking a rotative driving connection between machine parts. In the device shown, each member is Provided with four teeth of identical proportions and circumfere'ntial spacings to mesh with teeth of corresponding proportions and spacings on the companionate member. The arrangement of teeth is necessarily left-hand for one member and righthand for the other, as indicated by Figs. 7 and 8.

The top |46 of each tooth is the edge formed by the intersection of the planar face |48 with the curved face |50; the face |48 being substantially parallel to the central axis of the whirl chamber and substantially tangent to the inner wall of the chamber; the face |50 being essentially formed as a helicoid sloping gradually from the top edge |46 to the root line |52 of the adjacent tooth, the surface being generated by a straight line element maintained at aiixed distance fromv the central axis and advanced angularly and 1ongitudinally relative to that axis.

The companionate surfaces |40 and |42 of the members |02 and I 20 are maintained in their assembled contacting relation as shown in Fig. 6 by the resilient pressure of spring 52 which is transmitted through the spindle |36 to the movable member |20. The tangential passages or ports |24 are formed between the planar faces |48 of teeth on the fixed member |02 and the corresponding planar faces |49 of teeth on the movable member |20, the longitudinal dimension or depth .of the passages being constant and determined by the height of the teeth. 'I 'he circumferential dimension or width of each passage is progressively varied from a relatively Wide inlet dimension at the outer circumference |54 to a relatively narrower discharge dimension at the circumferential wall |68 of the whirl chamber ||6, as indicated in'Fig. 11, thereby providing a gradual reduction of flow area in the direction of fluid ow.

The width of the slots is regulable and dependent on the angle through which the member is rotated relative to the orifice member |02. Figs. 6 and 11 show the members |02 and |20 in an intermediate relative position to provide tangentially directed passages |24 of intermediate circumferential extent. It will be understood that a clockwise rotation of member |20, `as viewed from the left in Fig. 6, will reduce the width of each passage and that a counterclockwise rotation will increase the width, At the extreme limit of clockwise movement the passages are substantially closed due to the planar faces |49 of teeth on member |20 being in contact with the corresponding faces |40 of teeth on member |02. Throughout the entire range of adjustment, with surfaces |40 and |42 formed as described, each tooth surface |60 on the rotatable member |20 has a portion of its area maintained in contact with a corresponding portion of the companionate tooth surface |50 on the stationary member |02, thereby forming a Joint precluding leakage of fluid into the whirl chamber and causing uid to be admitted to the chamber only through the tangentlally directed passages l24.

The small degree of slope of surfaces |00 in an angular direction relative to a plane normal to the axis of rotation, and the parallel relation of straight line elements of the surfaces to such a plane, minimizes the possibility of the members |02 and |20 becoming rotatably shifted from their adjusted relative positions by the pressure exerted continuously by spring 52, as compared with surfaces of steeper inclination. Since the generating elements of the surfaces |50 are substantially straight lines tangent to a common circumference in planes normal to the central axis,

the direction of fluid ilow through tangential passages |24 is at all times parallel to such normal planes so that the maximum rotational movement of fluid is maintained in the whirl chamv ber throughout the capacity range.

For each advance in the opening direction, the increase in the iiow area of each passage |24 is accompanied by an increase in the angle of convergence between the side wall faces |40 and |49. The variation in flow area of the passages |24 is also accompanied by a variation in the depth of the whirl chamber which in the specific form shown constitutes an increase in depth for an increase in flow area, and a decrease in depth for a decrease in flow area, due to the relative movement of the contacting sloping tooth surfaces |50. This feature has been found advantageous in controlling the angle of spray at low operating capacities.

The tapered formation of the tangentially directed passages |24 results in a velocity of fluid flow through each passage increasing gradually to a maximum at the point of discharge of each tangential stream into the whirl chamber, each passage having the effect of a converging nozzle to reduce the friction and entrance losses in the passages themselves to a minimum, so that most of the available energy can be employed to impart an intensely whirling motion to`theuid in the whirl chamber.

In the modification of atomizer according to Fig. 12, the movable component |2l, being similar to part |20 of Fig. 6. cooperates with the re1- atively fixed orifice component |02 to fonn the tangential passages or ports |24 shown in Fig. 11; I'he part |2| is provided with an axial extension or plug which projects into the whirl chamber Ill to form an annular space |00 within the circumferential wall |66 to receive the liquid entering the Whirl chamber through ports |24. The plug is movable axially of the orifice in unison with part I 2|, thereby regulating the area available for iiuid flow through the annular space |62 between the conical end surface |64 of the plug and the conical end surface ||0 of the whirl chamber, the area of space |62 being varied from maximum to minimum in accordance with a corresponding variation in flow area of the tangential passages |24. If desired, the conical end |64 of the plug |68 may be arranged to contact the corneal surface ||8 in an extreme closed position as indicated by the dotted lines |60. The coordination of controls thus provided, one for tangential flow of liquid into the whirl chamber and another for the flow of whirling liquid within the chamber, tends to increase the eifectiveness of the centrifugal force available for maintaining a wider angle of spray at increasing capacities. Moreover, the quality of atomization has been found to be satisfactory throughouta wide range of capacities. including such low capacities at .which with other wide range burners it is normally diflicult to maintain combustion.

Fig. 13 illustrates a further embodiment of the invention in which an auxiliary supply of fluid is admitted to the whirl chamber in addition to the fluid admitted through the tangential ports, a

purpose of which is to control the angle of spray at varying flow capacities. In this arrangement, in a burner for example, the body portion |60 is fitted at one end with a barrel |10 as at |12, the orifice member |02 being removably held in xed relation to the barrel by the cap |00 as in Fig. 6. The movable atomizer component |14 is similar tothe previously described part |20 except for certain details pertaining to the admission of auxiliary fluid to the whirl chamber.

The opposite end of the body |60 is tted with a housing |16 through which the operating spindle |10 extends, and within which a partition wall |00 provides a seat 50 for spring 62 which maintains the companionate surfaces |40 and |42 of the fixed and movable components respectively in cooperative relationship. The packing |02 and packing gland |04 prevent leakage of pressure fluid from within the body |60. The outer end ofthe housing |16 is closed by a cap y|06 to provide a compartment |80 for van auxiliary v fluid, preferably air or steam, which may be admitted under pressure through the inlet connection |90. The spindle |10 has an extended end |02 exteriorly of the housing for the attachment of a suitable device or mechanism for rotating the spindle. The compartment is sealed against leakage by the packing |04,/the gland |06. and packing nut |90.

The spindle |10 is provided with a central passage 200 to which the auxiliary fluid is admitted from the compartment through an opening 202 adjacent one end, the passage 200 being open at its opposite end for delivering auxiliary fluid to the axial passage 204 extending through the movable atomizer component |14. The end of the spindle is supported concentrically of the barrel within the counterbore 206 and forms a duid-tight joint with the conical seat surface 200-as a result of the pressure exerted by spring i2. A driving connection between the spindle and part `|14 may beprovided by a lug or key llil on one part engaging a suitably recessed portion of the other part.

In this modification, the passages provided for fuel now are the same as described for Fig. 8,'the

lliquid entering the burner body under pressure through inlet port 2l. and being conducted through the annular barrel passage l2 and slot passages `|28 to the annular space Ill from which it passes throughftangential ports |24` to land through the whirl chamberand orifice.

The auxiliary fluid which may be a gaseous Huid, for example, such as air or steam, is maintained under pressure within the compartment il. and passes through the spindle passage Zoll and axial passage 204 into the whirl chamber ill where it exerts an axial pressure against the body of fuel within the chamber. The flow area velocity of fluid flow through the orifice and thereby cause a reduction in the angle of spray. At higher capacities, the ilow of auxiliary uid is automatically'cut ofi', or substantially reduced, due to the increased fuelpressure within the chamber IIB, whereby a practically normal angle of spray is produced for the particular capacity involved.

The utilization of an auxiliary fluid in the manner described therefore introduces an additional-factor contributing toa reduced variation in spray angle over a given range. As already discussed, a burner embodying the features of Figs. 6-11, independent of an auxiliary fluid supply, may be operated over a wide range of capacities with a smaller variation in spray angle than other burners due to the increased effectiveness of the centrifugal `forces relative to the axial forces`as capacities are increased. In a burner such as shown in Fig. 13, the increase in spray angle thus obtainable at the higher capacities is not affected by the use of an auxiliary fluid since the effect of the fluid at such capacities is negligible. However, the effect of the fluid is maximum at the lower capacities and causes the angle of spray to beillecreased. The modifyg ing effects on spray angleA are therefore combined; rst, a narrowing effect at the higher capacities incident to the control of fuel flow, and second, a narrowing effect at the lower capacities incident to the automatic supply ofthe auxiliary fluid. f 1

The auxiliary fluid also has a supplemental effect onv fuel atomization which enablesthe burner to be operated at capacities below the normal low limit of capacity determined by the regulation of fuel pressure and tangential port area. There is a further advantage in providing the maximum effect;v of the fluid at low capacities, since itis at such capacities that the combustion characteristicsof the spray become critical.`

Burners embodying selected features of the present invention have been successfully operaty ed atrvarious pressures and capacities, and an ficient combustion for a given variation in spray angle as compared with the lower capacity range T of other burners for a corresponding spray angle variation. Moreover the improved range of operation is obtainable with the same assembly o! parts instead of requiring a different combination of parts for each limited range which would necessitate an interruption of operation for dismantling and reassembly While the invention is disclosed specifically with reference to its use in an oil burner. it is to be understood that its application is more general, that its essential elements are useful in varversely of said axis.

2. In a fluid fuel burner for operation at different iiow capacities, means forming a whirl chamber having an outlet orifice, means for directing fluid fuel into said chamber in substantially tangential relation thereto comprising a plurality of plates circumferentially spaced in an annular band about said whirl chamber to form -iluid flow passages, and means for moving said plates relatively to regulate the iiow area oflsaid passages and thereby control the flow of fuel into said chamber.

3. In a fluid fuel burner for operation at different flow capacities, means forming a whirl chamber having an axially disposed outlet orifice, means for conducting fluid fuel to said chamber comprising a plurality of plates circumferentially spaced in an annular band about said whirl chamber and defining fluid flow passages for directing fuel into said chamber in substantially tangential relation thereto, and means for controlling the flow of fuel to said chamber including means for rotating said plates about separate axes. -v

4. In a liquid fuel burner having a circular outlet orice for atomized fuel, means forming a whirl chamber of circular cross section in axial communication with said orifice, said means including components one of which is movable relative to another, said components dening an inner cylindrical surface portion of said chamber of substantially larger diameter than said orifice and at a location longitudinally removed from said orifice said components forming passages of vregulable flow area for directing fuel into said chamber in substantially tangential relation thereto at said location of larger diameter, each passage being formed and arranged to provide a median line of ilow into said chamber in a plane substantially normal to the central axis of said chambenand means for moving one of said components relative to another for regulating said ow area.

5. In a fluent fuel burner for wide range operation, means forming a whirl chamber having an outlet orifice axially thereof, means for connecting said chamber witha supply of uent fuel under pressure including means forming one or more fluid flow passages of progressively decreasing flowr area in the direction of flow for directing fuel into said chamber in substantially tangential relation thereto, said last named means comprising coaxially arranged parts one of which is rotatable relative to the other, each passage having axially spaced defining walls formed of straight line elements in angular succession, each of said elements extending in substantially tangential relation to said whirl chamber in a plane substantially normal to the central axis of said chamber, and means for rotating said one part relative to the other for varying the flow area of each passage while maintaining the axial depth thereof substantially constant.

6. In a fluent fuel burner for wide range operation, means forming a whirl chamber having an outlet orifice axially thereof, meansI for connecting said chamber with a supply of fluent fuel under pressure including means forming one or more fluid flow passages of reducing taper in the direction of iiow for directing fuel into said chamber in substantially tangential relation thereto, each passage being formed to provide amedian line of flow therethrough in a plane substantially' formed with intermeshing teeth defining passages having their axes of flow extending in substan,

tially tangential relation to said chamber in a common plane normal to said common axis.

8. In a uent fuel burner having an outlet orifice, means forming a whirl chamber from which fuel is discharged through said orifice, said chamber and said orifice being formed about a common central axis, means forming passages for conducting fuel to said chamber comprising parts one of which is rotatable relative to the other about the axis of said chamber, said parts being formed with intermeshing teeth defining passages of regulable flow area extending in substantially tangential relation to said chamber, each part having tooth surfaces cooperating with similar tooth surfaces on the other part to define passages having circumferentially spaced `walls converging inwardly toward said c h a m b e r and axially spaced walls substantially parallel throughout, said axially spaced walls being formed of straight line elements in angular succession, each of said elements extending in substantially tangential relation to said chamber in a plane substantially normal to 'said axis, and means for rotating one of said parts for varying the relative positions of said cooperating tooth surfaces whereby the flow area of said passages may be increased or decreased. ,-9. In a fiuent fuel burner having an outlet orifice, means forming a whirl chamber from which fuel is discharged through said orifice, said chamber and `said orifice ,being formed about a common central axis, means forming passages for conducting fuel to said chamber comprising parts one of winch is rotatable relative to the A at theopposite side, said tooth surfaces on said parts cooperating to determine the circumferential width of a passage between corresponding planar surfaces and the axial depth of a passage between corresponding non-planar surfaces said planar surfaces being arranged parallel to said axis in substantially tangential relation to said chamber and said non-planar surfaces being formed of straight line elements directed substantially of said chamber in planes substantially normal to said axis, said formation and arrangement of surfaces providing Passages each havinng its median line of flow directed substantially tangentially of said chamber in a plane substantially normal to said axis. l

10. In a iiuent fuel burner, means forming a whirl chamber having an axially disposed outlet orifice, said means comprising members forming a cylindrical wall portion of said chamber nearer to the base of said chamber than to said orificeand forming a passage for directing fuel into said chamber substantially tangentially, said passage having its outlet in said cylindrical wall portion and having its median line of substantially tangential iiow into said chamber in a plane substantially normal to the common axis of said chamber and orince, one of said members being rotatable relative to the other about said axis, and means including said members for varying the depth of said chamber and simultaneously varying the flow area of said passage substantially throughout its length.

11. 1n a fluid atomizer having an outlet orifice connected toa source of liquid under pressure, means for imparting a whirling motion to liquid from said source in a zone coaxial withl said orifice and for causing said whirling liquid to be moved longitudinally of said zone for discharge through said orifice at varying rates. to provide an expanding spray, said means comprising parts having cylindrically formed surface portions defining a cylindrical boundary for said whirling zone at a diameter substantially greater ,than the diameter of said orifice, said parts having other surface portions defining a passage for directing said liquid into said whirling zone substantially tangentially of said cylindrical boundary at a distance from said orifice requiring said whirling liquid to move longitudinally of said zone before entering said orifice, said passage having its axis of flow in a plane substantially normal to the axis of said whirling motion, one of said parts being rotatable relative to another of said parts for varying the flow area of said passage substantially throughout itsV length while hunting the variation in the cross section of said passage to a direction substantially parallel to said normal plane.

12. In a fluid atomizer having a whirl chamber and its outlet orifice formed about a common longitudinal axis, said orifice being of substantially smaller diameter than said chamber to provide a restricted outlet therefrom, means comprising parts having surface portions forming a cylindrical wall portion of said chamber at a location adlacent the base of said chamber, said parts having other surface portions forming a passage for directing liquid into said chamber substantially tangentially of said cylindrical wall portion to impart a whirling motion to said liquid at a distance from said orifice requiring the whirling liquid to move longitudinally of said chamber before entering` said orifice, said passage having its wallsarranged to provide a median line of iiow through said passage in a plane as'zaass L 7 substantially normal to said common axis. said parts including a part movable relative to another of said parts, and means Vfor moving said movable part to include rotation relative to said other part for regulating a cross sectional dimension of said passage.

13. In a fluid atomizer having a whirl chamber and its outlet orifice formed about a common longitudinal axis, said orifice being of substantially smaller diameter than said chamber to provide a restricted outlet therefrom, means omprising parts having surface portions forming a cylindrical Wall portion of said chamber at a location adjacent the base of said chamber, said parts having other surface portions forming a passage for directing liquid into said chamber substantially tangentially of said cylindrical Wall portion to impart a whirling motion to said liquid at a distance from said oriilce requiring the whirling liquid to move longitudinally of said chamber before entering said orifice, said passage having its walls arranged to provide a median line of ow through said passage in a plane substantially normal to said common axis, said parts including a part movable relative to another of said parts, and means for moving said movable part to include rotation relative to said other tion of iiow in a plane substantially. normal to the axis of whirl. varying the rates of fuel now by varying the cross-section of said streams while maintaining their axial dimensions substantially constant and their points of entry into said whirling zone 'substantially tlxed in relation to said ori- `tlce, and admitting an auxiliary iiuid into said nwhirling zone at a location rearwardly of the points of entry of said streams of fuel, said auxiliary fluid being admitted to said zone in a stream axially aligned with said orice and at a pressure less than the pressures existing within said zone at the higher rates of fuel iiow to increase the enective axial velocity of fluid iiow through said orifice only at the lower rates.

16. In a liquid fuel burner for wide range operation, means comprising parts forming a whirl' chamber having a cylindrical wall portion c adjacent its base and an axially disposed outlet part for eiecting a variation in the cross section i of said passage greater in a direction transversely of said axis than in a direction parallel to said axis.

14. In a fluid atomizer having a whirl chamber and its outlet orifice formed about a common longitudinal axis, said orifice being of substantially smaller diameter than said chamber to provide a restricted outlet therefrom, means comprising parts havingsurface portions forming a cylindrical wall portion of said chamber at a location adjacent the base of said chamber, said parts having other surface portions forming a passage for directing liquid into said chamber substantially tangentially of said cylindrical wall portion `to impart a whirling motion to said liquid at a distance from said orifice requiring the whirling liquid to move longitudinally of said chamber before Arentering said orifice, said passage having its walls arranged to provide a median line of flow through said passage in a plane substantially normal to said common axis, said parts including a part movable relative to another of said parts, and means for moving said movable part to include rotation relative to said other part for regulating the flow area of said passage while limiting the variation in the cross section of said passage substantially to a direction transversely of said axis.

15. In the atomization of liquid fuel wherein fuel under pressure is directed tangentially of a whirling zone for subsequent discharge through an orifice to produce a divergent spray of atomized fuel, and'wherein at widely varying rates of fuel flow the angle of spray varies from a relatively Wide angle at the lower rates to an appreciably narrower angle at the higher rates, the method of maintaining minimum variation in the angle of spray throughout a predetermined range of fuel iiow rates which comprises directing said fuel in a plurality of streams tangentially into a whirling zone of cylindrical formation at a location remote from its outlet orince of restricted diameter, each of said streams having its direcorifice of restricted diameter at its opposite forward end, said parts including a part movable relative to another of said parts, said parts having surface portions mutually forming a passage through a circumferential wall of said chamber for directing fuel under pressure into said chamber substantially tangentially, said passage being formed to provide a median line of fiow therethrough in a plane substantially normal to the central axis of said chamber, means for moving said movable part to vary the flow area of said passage, and means forming an axially disposed secondary orifice through the base of said chamber for supplying an auxiliary iiuid under pressure to said chamber.

1'7. In a liquid fuel burner for wide range operation, means comprising parts forming a` whirl chamber having a cylindrical wall portion. adjacent its base and anaxially disposed outlet orifice of restricted diameter at its opposite forward end, said parts including a part movable relative to another of said parts, said parts having surface portions mutually forming a passage through said cylindrical wall portion of said chamber for directing fuel under pressure into said chamber substantially tangentially, saidpassage being formed to provide a median line of flow therethrough in a plane substantially normal to the central axis of said chamber, means for moving said movable part to vary the flow area of said passage throughout its length while maintaining its axial dimension substantially constant, and means forming an axially disposed secondary orifice through the base of said chamber for supplying an auxiliary uid under pressure to said chamber.

18. In a liquid fuel burner for wide range operation. means forming a whirl chamber of circular cross-section having an outlet orifice, said chamber and said orifice being formed about a common central axis, means forming a passage for directing fuel into said chamber in substantially tangential relation thereto comprising members one of which is rotatable relative to the other about the axis of said chamber, means for rotating said one member for regulating the flow area of said passage substantially throughout its length and thereby the flow of fuel into said chamber, and means on one of said members movable longitudinally of said axis for controlling the flow of fuel into said orifice.

' LAMBERT KOOISTRA.

Certificate of Correction Patent No. 2,372,283. March 27', 1945.

LAMBERT KOOISTRA It is hereby certified that errors appear in the printed specification of the above numbered patent reqnirin correction as follows: Page 3, first column, line 68, for the word oce read on' c; page 5, second column, line 57, claim 4, after orifice insert a comma; page 6, second column, line 5, claim 9, after surfaces insert a comma line 12, for havinng read having; page 7, second column, line 24, claim 16, for a circumferential wall read said cylindrical wall portion; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 12th day of November, A. D. 1946. v

LESLIE FRAZER,

First Assistant 'ommssz'oner of Patents. 

